Seasonal Variation in the Measurement of GOES-16 ABI Channel-to-Channel Registration

Abstract

An Image Navigation and Registration (INR) Performance Assessment Tool Set (IPATS) was developed to assess the US Geostationary Operational Environmental Satellite R-series (GOES-R) Advanced Baseline Imager (ABI) and Geostationary Lighting Mapper (GLM) INR performance. Channel-to-channel registration (CCR) is one of the five INR performance metrics produced by IPATS. A seasonal variation is observed in the CCR assessment in north-south direction when one or both channels are reflective. However, indirect CCR, calculated as the difference of NAV measurements between two channels, does not present the similar seasonal variation. The phenomenon of the seasonal variation coincides with the annual change of the subsolar point location. The amplitude of the seasonal variation is related to the length and the direction of the shadow. Direct CCR, measured by IPATS directly, performs better than indirect CCR when both channels are visible wavelengths or emissive channels. For all other channel pair combinations, the assessment of indirect CCR is more accurate.